I.P insulin injection in mice. - KravitzLab/KreedLabWiki GitHub Wiki

Material needed :

The insulin powder is very very concentrated, as like 27 units per mg, furthermore, it cannot be disolved in PBS or miliQWater, it needs to be dissolved in acidic solutions (pH < 3)

Stock solution of 1.2 unit/mL.

  • Take 0.9 mg of insulin powder with the precision scale.
  • Add the powder to a 20 mL solution of PBS in a beaker
  • UNDER HOOD, take a few drops of 35% HCL.
  • With the pH meter, look at the pH of your Insulin + PBS solution. Then add DROP BY DROP the HCL and mix gently the solution. Stop when your reach pH ~ 2.5. (It should take 1-2 drops).
  • Stir the Solution for about 5 minutes to make sure the insulin dissolves.
  • Put the solution in a conic tube (50 mL).

You now have a a 0.9 * 27 / 20 = 1.2 Unit/mL solution of insulin.

Diluted solution of 0.1 unit/mL

  • From this stock solution with 1.2 unit per mL at 20 mL, we now want a 0.1 unit/mL solution of 15 mL.
    CiVi=CfVf (Ci : Initial concentration ; Vi : initial volume ; Cf = Final concentration, Vf = Final volume) So Vi is the volume we need to take from the stock solution. Vi = CfVf/Ci = 0.1 * 15 / 1.2 = 1.25 mL. So in a conical tube of 15 mL, put 1.25 mL of stock solution with 13.75 mL of PBS.

_With this volume of PBS added, the pH should be back at around 7, which is the lower range of acceptability for insulin pH in human injection. Check it with the pH Meter.

  • Mix the solution you obtained (a few ups and downs)
  • Take an ependorf of 5mL and with a syringe with a filter, push out 3 mL of solution to have a filtered insulin solution.
  • Stock the solution at 4°c.

Adequate i.p injection

According to this protocol , the typical range for insulin injection in mice is between 0.5U/kg to 2U/kg. So for injection :

  • Weight your mouse (Ex : 20 g = 0.02 kg)
  • Calculate the amount you need to inject : if you want to do 0.5 U/kg for example 0.02 * 0.5 = 0.01 U
  • Calculate how much you need to take from the filtered solution CiVi = CfVf Vi = O.O1/0.1 Vi = 0.1 mL.